Corrosion mitigation in metal-air batteries

Abstract

Corrosion mitigation in a metal-air battery includes displacing an electrolyte within a gap of the metal-air battery with a liquid. The liquid may be substantially nonreactive with the electrolyte, and the anode of the metal-air battery is less reactive with the liquid than with the electrolyte. Upon displacement of the electrolyte from the gap, the liquid may remain in the gap of the metal-air battery to reduce the likelihood of corrosion of the anode and, therefore, reduce the power drain of the battery resulting from such corrosion. To return the metal-air battery to an activated state for generating power, the electrolyte may be moved back into the gap to displace the liquid. A fluid circuit may be in fluid communication with the gap and may displace one of the liquid and the electrolyte in the gap with the other one of the liquid and the electrolyte from the fluid circuit.

What is claimed is: 
     
       1. A system comprising:
 a metallic anode; 
 an air cathode spaced apart from the metallic anode such that the air cathode and the metallic anode define a gap therebetween; and 
 a fluid circuit in fluid communication with the gap, the fluid circuit including a flowable form of an electrolyte and a liquid, wherein the liquid is substantially immiscible with the flowable form of the electrolyte and is substantially nonreactive with the flowable form of the electrolyte, the metallic anode is less reactive with the liquid than with the flowable form of the electrolyte, and the liquid is movable in the fluid circuit to displace the flowable form of the electrolyte in the fluid circuit. 
 
     
     
       2. The system of  claim 1 , wherein the fluid circuit includes a pump actuatable to displace one of the liquid and a flowable form of the electrolyte in the gap with the other one of the liquid and the flowable form of the electrolyte from the fluid circuit. 
     
     
       3. The system of  claim 1 , wherein the fluid circuit and the gap define a substantially closed system as the liquid and the flowable form of the electrolyte are displaced back and forth in the gap. 
     
     
       4. The system of  claim 1 , further comprising a housing containing the metallic anode and the air cathode, the gap between the metallic anode and the air cathode disposed within the housing. 
     
     
       5. The system of  claim 1 , wherein the fluid circuit includes a first reservoir that holds one of the liquid and the flowable form of the electrolyte while the other one of the liquid and the flowable form of the electrolyte is disposed in the gap. 
     
     
       6. The system of  claim 5 , further comprising a second reservoir including a carrier, the second reservoir in fluid communication with the first reservoir such that the carrier is movable from the second reservoir to the first reservoir for mixing with the flowable form of the electrolyte, the mixture of the carrier and the flowable form of the electrolyte having a greater flowability than the flowable form of the electrolyte alone. 
     
     
       7. The system of  claim 1 , wherein the flowable form of the electrolyte includes an aqueous solution of the electrolyte. 
     
     
       8. The system of  claim 1 , wherein the liquid is less conductive than the electrolyte. 
     
     
       9. The system of  claim 1 , wherein the liquid includes an oil. 
     
     
       10. The system of  claim 9 , wherein the liquid includes one or more of a mineral oil and a silicone oil. 
     
     
       11. The system of any of  claim 1 , wherein the liquid is inviscid. 
     
     
       12. The system of  claim 1 , wherein the liquid has a different density than the electrolyte at room temperature. 
     
     
       13. The system of any of  claim 1 , wherein the metallic anode includes aluminum. 
     
     
       14. The system of any of  claim 1 , wherein the flowable form of the electrolyte includes crystallized electrolytes. 
     
     
       15. The system of  claim 1 , wherein the electrolyte includes one or more of sodium hydroxide and potassium hydroxide. 
     
     
       16. The system of any of  claim 1 , further comprising a lithium-ion battery, wherein the metallic anode, the air cathode, and the electrolyte form a metal-air battery, and wherein the metal-air battery is electrically coupled to the lithium-ion battery for charging the lithium-ion battery using electrical power generated by the metal-air battery. 
     
     
       17. A method of operating a metal-air battery, the method comprising:
 supplying a flowable form of an electrolyte from a fluid circuit to a gap defined between a metallic anode and an air cathode of the metal-air battery; 
 with the flowable form of the electrolyte disposed in the gap between the metallic anode and the air cathode, generating electrical power at the metal-air battery; and 
 selectively moving a liquid from the fluid circuit into the gap, the movement of the liquid into the gap displacing the flowable form of the electrolyte from the gap to the fluid circuit and substantially limiting a reactant of a reaction occurring at the metallic anode in the presence of the flowable form of the electrolyte, wherein the liquid is substantially immiscible with the flowable form of the electrolyte.